THE NAUTILUS. 115 



Vitrea radiatula circumstriata Taylor. Arkadelphia. Quite 

 rare, generally associated with arborea. 



Vitrea (Paravitrea) signijicans (Bland). West of Arkadelphia 

 in the foothills. Rare! 



Vitrea wheatleyi (Bland) ? Arkadelphia. This species, which 

 cannot be placed anywhere else among the Zonitidce collected, 

 is either wheatleyi, or a variety of it. 



Euconulus cherdnus trochulus {Rein.). Arkadelphia. Fairly 

 common. 



Euconulus chersinus polygyratus (Pils. ) ? Arkadelphia. 



Zonitoides arborea (Say). Arkadelphia ; also along Little 

 Deceiper Creek, and at Gurdon. Generally distributed. 



Zonitoides {Pseudohyalina) minuscula (Binney). Arkadelphia. 



Gastrodonta demissa brittsi (Pils.). In the hills five miles 

 northwest of Arkadelphia. Smaller than typical brittsi, and 

 rare. 



Pyramidula alternata (Say). Arkadelphia, Gurdon, Whelen, 

 and six miles east of Whelen in the southeast end of the County. 



Helicodiscus parallelus (Say). Arkadelphia, west of the town 

 near Little Deceiper Creek. Very rare! 



Circinaria concava (Say). Limestone region west of Arka- 

 delphia, and ' ' Big Bluff ' ' on the Ouachita River, two miles 

 north of Arkadelphia. 



Polygyra leporina Gould. Arkadelphia and Gurdon. Com- 

 mon in most of the low lands. 



Polygyra dorfeuilliana Lea. In low hills west of Arkadelphia, 

 Gurdon. Rare! Nearly always found under small pieces of 

 bark, seldom under logs and stones. 



Polygyra infleda (Say). Arkadelphia, Gurdon, Whelen, and 

 southeastern corner of the County. 



Polygyra albolabris (Say). Arkadelphia. Rare! This does 

 not appear to be the variety alleni Wetherby, to which all of 

 the shells of this type west of the Mississippi River have been 

 referred. 



Polygyra divesta (Gould). Arkadelphia, Crawford's Mill on 

 Big Deceiper Creek, Gurdon. 



Polygyra zaleta (Binney). Woods west of Arkadelphia. 

 Rare! 



